There are many circumstances in which there is a need for a fixing element for fixing an article in position, more particularly in a through bore which is only accessible from one side of the structure to which the article is to be fixed. A fixing element of that kind, which is disclosed in German patent specification No. 2 520 586 comprises a cylindrical upsetting sleeve with an end of a flange-like configuration, and a cylindrical insert member which is disposed in the sleeve and which has a flange-like head, the outside diameter of which is equal to the outerside diameter of the upsetting sleeve. The underside of the head of the insert member is in direct contact against the adjoining end face of the sleeve, to provide for the transmission of pressure therebetween, and the upsetting sleeve is deformable in a bead-like configuration by virtue of an axial pulling force applied to the insert member. Between the outer periphery of the cylindrical insert member and the inner periphery of the sleeve, in the end region thereof, there is a material bonding connection providing a positive connection in respect of the materials involved. The connection may be in the form for example of spot welds.
Although that fixing element has enjoyed wide-spread use in practical situations it nonetheless suffers from a number of disadvantages. For example the fixing element is disposed in a round hole in the structure to which it is to be secured, and thus does not have any means for preventing rotation thereof. In addition the raised portions formed at the material bonding locations such as the spot welds referred to above mean that the structure to which the fixing element is to be fixed must have bores of enlarged size in order satisfactorily to accommodate the fixing element.